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Old Jun 03, 2012, 04:05 PM
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looking good cant wait to see how it comes out
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Old Jun 03, 2012, 04:17 PM
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I can post news about custom E-gyro too.

Sent to a machinist an original Duratrax flywheel for some lightening too, ordered a custom split wheel shaft and some other machining process on the 04B 32T sprocket about a week ago.

Once at home (past saturday) I started to put all the parts together and first was fitting the outrunner can inside the flywheel. Iīve ordered a slight bearing size change going from 13mm OD to 14mm. These 14mm OD bearings feature an inner bore of 8mm, and this tip makes shaft design much simpler.

Iīve removed the outrunner motor bearings (8mm OD) so I can install the wheel shaft through motor case. As you can see, wheel shaft right half feature a disc that acts as motor mount. I need just one screw to lock it to the shaft.

My custom E-gyro installed on the swingarm.





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Old Jun 03, 2012, 04:39 PM
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More news...

As I told you from the very early proyect development steps, I wanted to keep gyro electronics outside wheel case.

This lead to find a bigger bearing that allowed to pass motor wires through its inner ring. Iīve chosen 15x10x4 flanged ones...

Now itīs time to cut three slots at wheel shaft to let wires out. Iīve installed a disc mill at the machine to cut these 2.5mm wide/deep slots. Iīve left some room among them in order not to weaken wheel shaft nor offcenter wheel bearing.

I was also in the need to cut two spacers that will keep wheel centered. Right one also feature an open arc to give way to motor wires. Iīve tried to chamfer all sharp edges in order not to have shortcuts.

As you can see in pics, gyro wires go along right swingarm leg far from any rotating part (chain and sprocket at left side).




Now itīs time to install gyro electronics and test it. For the very early testing, Iīll power it up from a 2S lipo, a plane esc and a modified servo tester. This system will allow to change gyro rpm with a single potentiometer. For further testing I plan to install a car esc just the way I told you in a previous post (reversed channel).

More news soon.

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Old Jun 04, 2012, 06:50 AM
AR Racing
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Italy, near Milan
Joined Mar 2005
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Hi, you should have left more material in the outer part of the gyro, in order to have, with a little more weight,a much higher gyro effect.
How many kv has the gyro motor?
Ciao
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Old Jun 04, 2012, 08:09 AM
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Quote:
Originally Posted by Jena67 View Post
Hi, you should have left more material in the outer part of the gyro, in order to have, with a little more weight,a much higher gyro effect.
How many kv has the gyro motor?
Ciao
Ciao Antonio.

Youīre the second one that tells the same about the flywheel. Manu was the first, this early morning...

:

Starting from a Duratrax unit, Iīve kept the steel rings that hold weights in position. Flywheel also keeps threaded holes from stock unit so I can load it with steel rings for a perfectly balanced weight increase.

About motor Kvs, I purchased it a lot of time ago and I canīt remember it. Considering Iīve purchased it for a 3D foamie, maybe about 1000Kv or so...

I prefer not to overload it at the very initial testing, thatīs the reason of "extreme flywheel lightening"...

Grazie.
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Old Jun 04, 2012, 08:23 AM
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looking very nice so far.

Altough with all the drilled holes in the flywheel, the sound will be awesome.
One driver here machined an aluminium flywheel for the ARx eGyro, that had (i think) 3 holes in it. It howled quite loud
I have one of the old (lighter) flywheels, and a new/current one for my ARx, and use them to finetune the bike to the different tracks (using a fixed rpm gyro).
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Old Jun 04, 2012, 10:43 AM
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Quote:
Originally Posted by trf_414_m2 View Post
Ciao Antonio.

Youīre the second one that tells the same about the flywheel. Manu was the first, this early morning...

:

Starting from a Duratrax unit, Iīve kept the steel rings that hold weights in position. Flywheel also keeps threaded holes from stock unit so I can load it with steel rings for a perfectly balanced weight increase.

About motor Kvs, I purchased it a lot of time ago and I canīt remember it. Considering Iīve purchased it for a 3D foamie, maybe about 1000Kv or so...

I prefer not to overload it at the very initial testing, thatīs the reason of "extreme flywheel lightening"...

Grazie.
What is this mill you are using?

You found an outrunner that fits perfectly inside where the dx450 clutch used to be?? Im jealous! I did the research a while ago to try to make my own. I have the esc and mini servo tester and outrunner, but no machining ability. I stopped to work on website stuff instead lol.

Is the flywheel your using the stock steel or the aftermarket aluminum? The aluminum version cuts weight in half.
- stock flywheel w/o weights= 349gr
- stock with weights= 536gr
- alum. flywheel w/o weights= 164gr
- alum. assembled gyro flywheel= 351gr

I have aluminum aftermarket flywheel in my dx450 with all weights in its about same weight as the original with NO weights. I get same gyro feeling, but for half the weight!! So Im confused why you would not use the weights in your system, its NEEDED on dirt, especially if your bike is 1/4 scale. My opinion.

Very excited.
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Old Jun 04, 2012, 01:30 PM
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Gartenz..

Thanks for the advice about the sound. Iīll contact Antonio and ask if would be possible to extract all air from an ARX wheel....



Johnny, this is my Proxxon milling station.

For lathe operations I used to go to a machinist. I didnīt find an outrruner that directly fit inside Duratrax flywheel, so I get a slightly larger unit that measure 27.8mm dia while flywheel bell is about 26mm dia. The machinist enlarged the bell giving appropiate tolerances for the ounrunner can to press fit (0.05mm or so). Also added a drop or two of threadlock and press both parts together.

Iīve started from a steel flywheel purchased a long time ago, prior to aluminum option part release date.

About gyro effect, you can get it by placing weight at a fixed radius or increasing rpms. Two flywheels same design (weight placed at the same radius for gyro momentum calculation), one half the weight of the other (aluminum against steel) get same gyro effect when lighter unit doubles rotating speed of the other.

In your case, stock steel flywheel with no weights have a smaller radius for momentum calculation than aluminium unit, where all weights are placed much closer to the outer circumference (less weight at a bigger radius).

For better understanding, check ARX "ringed" E-gyro. These guys manufactured a plastic flywheel that feature a steel ring/tube on the very outside. This tube is placed so far from the center of the wheel that can create a lot of gyro effect at low rpms.

And a tip about E-gyros, need more rpms? switch to 3s for gyro power to get 50% more effect...

This is the main problem about gear gyros. You can mess with the weights but you canīt gear it up for faster spinning. And the more ballast you put, the harder for main motor to launch it...

Hope this "brief explanation" helps.

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Old Jun 05, 2012, 11:04 AM
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California central coast
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Sorry Cesar, I understood all that already.

I guess Im confused if your going to use the stock flywheel steel weights or not. I was just trying to point out that by using an aluminum flywheel, you can keep using the stock steel weights. Instead it sounds like your using steel rings for weight only? Or will the stock weights be used also? If your not going to use all 20 of those weights, I think thats a mistake. That is a great design feature you would be removing from system! Thats what manuspain and Gartenzwerg are trying to tell you. Your smarter than me, so you doing a great job none the less.

I dont think running at 3s should be the answer to get stability if 2s doesnt work. System should be stable at 2s, and at 3s you need to run gyro slower if too fast. I take it you picked the 1000kv motor because the arx uses about same speed too? I understand the arx egyro, dmincin's ricky gyro, Manfred Hallman's ricky gyro. I understand the basics of gyro force calculations.
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Old Jun 05, 2012, 04:44 PM
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Sorry Johnny, seems I misunderstood your explanation and tried to tell you things you already know...

The plan to tune the gyro is

1) Check system as seen at the pics.

2) Load the flywheel by rings only (if needed), no barrels at all.

3) Swap to 3S.

4) Get a faster motor if previous points didnīt work.

I donīt have info about the motor ARX guys are installing on their E-gyro, but I think "true 8000 rpm" flywheel (or even 12.000 rpm at 3S) would work.
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Old Jun 11, 2012, 02:35 PM
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First test.

E-Gyro CSC primera prueba en banco (2 min 25 sec)


Iīm so happy about the way this little motor spins the "unloaded" flywheel, and makes me confident about the performance of a loaded one or a 3S powered unit.

As you can see at the video, the test system feature a motor, a plane esc and a modified servo tester. All these items powered by 2S lipo.

Iīve accelerated it till half pot travel (EPA 50%) and the flywheel sounds like it was ready for take off. I was warned by Gartenz about this and itīs awesome to hear it in person.

I plan not to spin it faster till I install the complete wheel. Itīs a safety precaution...



Hope you like it.
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Old Jun 11, 2012, 03:33 PM
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Lovely!
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Old Jun 11, 2012, 04:07 PM
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It sounds like one of the instruments used in the start of Hawkwind's Silver Machine!
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Old Jun 11, 2012, 04:31 PM
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Nice. It looked like it was spinning wrong direction though.
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Old Jun 11, 2012, 05:13 PM
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Hi Johnny.

No wrong spin direction, but Iīve watched the video several times and seems to...



Maybe an optical effect, because seems to speed up in opposite direction while braking in the right one.

Iīll double check it tomorrow, but this motor and esc were installed on a foamie lot of time ago and I left motor wires colour coded for proper propeller rotation.

See you all tomorrow.
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